Whenever blood is treated outside the body, such as in an oxygenator or heat exchanger, it is often desirable to measure blood temperature. Conventionally this has been done external to the oxygenator or other device by breaking a blood line to connect into the line a sterilized coupling having a temperature probe inserted through a wall. When a heat exchanger is used, two sterilized couplings are sometimes required.
Maurer U.S. Pat. No. 899,313 shows a thermometer well with a hollow body that is mounted in the wall of a vat and that has external threads outside the vat for inwardly forcing a thermometer tube so as to make firm, heat-conducting contact between the thermometer tube and the interior walls of the well.
Rees U.S. Pat. No. 2,161,432 shows a thermometer well with a corrosion resistant tube sealed at one end and threadedly received in a plug at the other, the plug having external threads for mounting in a reservoir and internal threads for securing a thermometer.
Switzer U.S. Pat. No. 3,081,631 shows a thermometer well broadly similar to Maurer and Rees for use in pipes.
Meyers U.S. Pat. No. 3,703,892; Schapker U.S. Pat. No. 3,833,115; and Doyle U.S. Pat. No. 3,913,402 each show rubber-like sheaths for clinical thermometers.